As I understand it the backports ppa only has packages for precise and quantal. Since you are not running either one, nothing will be picked up. Also I think the backports ppa is in the 4.4.9x category not 4.4.8x.

Well, if you want to take a chance you can alter the kubuntu backports on your distro to say precise or quantal. This can be done through synaptic or the command line. If you open synaptic and look at the repositories, I would guess yours says oneiric for kubuntu backports. If you change this to say precise and update then you would update to what KDE version is in the precise backports. You can go to https://launchpad.net/~kubuntu-ppa/+archive/backports to see what is there